Central Mechanisms in Speech Motor Control Studied With H215O PET

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ClinicalTrials.gov Identifier: NCT00001308

Recruitment Status :
Terminated

First Posted : November 4, 1999

Last Update Posted : May 22, 2018

Sponsor:

National Institute on Deafness and Other Communication Disorders (NIDCD)

Positron Emission Tomography (PET) is a technique used to investigate the functional activity of the brain. The PET technique allows doctors to study the normal biochemical and metabolic processes of the central nervous system of normal individuals and patients with neurologic illnesses without physical / structural damage to the brain. Radioactive water H215O in PET scans permits good visualization of areas of the brain related to speech.

Most of the PET scan studies conducted have concentrated on learning about how language is formed and decoded. Few studies have been conducted on speech production. This study aims to use radioactive water (H215O) and Positron Emission Tomography (PET scan) to measure blood flow to different areas of the brain in order to better understand the mechanisms involved in speech motor control.

When a region of the brain is active, it uses more fuel in the form of oxygen and sugar (glucose). As the brain uses more fuel it produces more waste products, carbon dioxide and water. Blood carries fuel to the brain and waste products away from the brain. As brain activity increases blood flow to and from the area of activity increases also. Knowing these facts, researchers can use radioactive chemicals (H215O) and PET scans to observe what areas of the brain are receiving more blood flow.

Researchers will ask patients to perform tasks that will affect speech, voice, and language. At the same time patients will undergo a PET scan. The tasks are designed to help researchers observe the blood flow to brain areas associated with voicebox (laryngeal) functions, movement of muscles in the jaw, tongue, and mouth, and other aspects of motor speech.

Special studies will be conducted to evaluate how certain therapies and tasks can draw out symptoms in illnesses in which speech and language are affected. Results of these tests will be used in other studies to evaluate the neurologic mechanisms of diseases like Tourette's syndrome and parkinson's disease.<TAB>...

The primary objective of this protocol is to use multimodal neuroimaging combining complementary electrophysiological and hemodynamic methods to characterize brain-language relationships in healthy subjects and those with neurological disorders that affect speech and language. A secondary objective is to utilize these findings to develop evaluation measures for future treatment studies.

Study Populations

We will focus on four neurological disorders that affect language processing post-stroke aphasia, traumatic brain injury, epilepsy and developmental stuttering. Each constitutes a significant clinical problem central to the NIDCD s mission. These disorders can impair language at several levels - from its elementary perceptual and motor features, the peripheral building blocks of language, to higher levels of language formulation, including word, sentence and narrative processing.

Design

We will utilize a set of tasks designed to evaluate language at the levels at which clinical pathology emerges. We will combine hemodynamic (functional MRI) and electrophysiological (EEG, MEG) modalities to capitalize on the superior spatial resolution of the former and temporal resolution of the latter methods. Whenever possible the same task paradigms are used with both techniques. We will conduct crosssectional sub-studies, addressing specific questions in each of the disorders of interest; we will also conduct longitudinal sub-studies of recovery and neuroplastic reorganization in post-stroke aphasia.

Outcome Measures

Outcome measures include speech-language and psychological tests, measures of behavioral performance during scanning and corresponding MRI, EEG and MEG data. Relationships between these datasets will be evaluated using statistical analytic packages.

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Significant abnormalities on the general physical examination unrelated to the stroke or TBI

Unable to undergo MRI studies due to pacemakers, aneurysm clips, cochlear implants, shrapnel fragments or a significant history of exposure to small metallic objects which might have become lodged in the tissues of the head or neck or who require hearing aids.

Subjects who are pregnant are excluded from the PET and MRI tests in this study.